This VAS allows mobile/landline subscriber not to pay his telco for calls.
Instead of this he appeals to Smartswitch using one of free-of-charge methods (web browser, calling to access number with no pickup, etc).
Smartswitch initiates calls and bridges them together into a 2-way call.
Subscriber pays to Smartswitch owner for these calls (the calls are deducted from user's balance), or they might be included into monthly fee.
And Smartswitch owner in turn pays to telco for user's calls.
Smartswitch owner could have better price conditions with the telco as he is a wholesale customer on the contrast with a user who is the retail customer for telco.
Following options are available for user to request a callback from Smartswitch: